Vessel sealing instrument

ABSTRACT

A bipolar electrosurgical instrument is provided. The bipolar electrosurgical instrument includes first and second shafts each having a jaw member extending from a distal end thereof and a handle disposed at a proximal end thereof for effecting movement of the jaw members relative to one another. A first conductive lead is adapted to connect to a first electrical potential and a second conductive lead is adapted to connect to a second electrical potential. One of the first and second conductive leads extends through the pivot to connect to a respective jaw member.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 12/895,020 filed on Sep. 30, 2010, now U.S. Pat. No. 9,005,200,the entire contents of which are incorporated herein by reference.

BACKGROUND

Technical Field

The present disclosure relates to forceps used for open surgicalprocedures. More particularly, the present disclosure relates to aforceps which applies a combination of mechanical clamping pressure andelectrosurgical current to seal tissue.

Description of Related Art

Electrosurgical forceps, e.g., commonly used in open surgicalprocedures, are configured to grasp, dissect and/or clamp tissue.Electrosurgical forceps is a simple plier-like tool which utilizes bothmechanical clamping action and electrical energy to respectivelyconstrict vessels and effect hemostasis by heating the tissue and bloodvessels to coagulate, cauterize and/or seal tissue. Electrosurgicalforceps may be configured for monopolar or bipolar use. For the purposesherein, the present disclosure is directed to electrosurgical forcepsthat are configured for bipolar use.

Bipolar electrosurgical forceps (forceps) utilize two generally opposingelectrodes that are disposed on the inner opposing surfaces of jawmembers associated with the end effector of the forceps and that areboth electrically coupled to an electrosurgical generator. Eachelectrode is charged to a different electric potential and includes arespective seal plate; the seal plates are isolated from each other.Design of the isolated seal plates requires separate and unique wires toenable RF energy for vessel sealing (opposite poles for alternatingcurrent). Typically, because of the limited space of the forceps, one ofthe wires is routed directly to one of the seal plates and the otherwire is routed indirectly around, i.e., “looped,” about a pivot memberthat pivotably couples a pair of shafts associated with the forceps.Looping one of the wires around the pivot member may result in the“looped” wire being exposed to the surgical environment when the jawmembers are moved, e.g., from an open to clamped position. As can beappreciated, exposing the wire to the surgical environment may result indamage to the wire, which, in turn, may decrease the operative life ofthe forceps. Moreover, “looping” the wire around the pivot member mayincrease manufacture costs, i.e., more wire is needed to loop around thepivot member, and may increase manufacture time of the forceps, i.e.,more time is needed to loop the wire around the pivot member.

SUMMARY

The present disclosure provides a bipolar electrosurgical instrument foruse in open surgery. The bipolar electrosurgical instrument includesfirst and second shafts each having a jaw member extending from a distalend thereof. A handle is disposed at proximal ends of the shafts foreffecting movement of the jaw members relative to one another about anintegrally formed bifurcated pivot member that is supported on one ofthe jaw members. The jaw members are movable relative to one anotherabout the pivot member from a first position wherein the jaw members aredisposed in spaced relation relative to one another to a second positionwherein the jaw members cooperate to grasp tissue therebetween. Aproximal shaft connector operably couples to one of the first and secondshafts and is configured to connect the bipolar electrosurgicalinstrument to a source of electrosurgical energy providing first andsecond electrical potentials. A first conductive lead is adapted toconnect to the first electrical potential and a second conductive leadis adapted to connect to the second electrical potential. One of thefirst and second conductive leads extends through the pivot to connectto a respective jaw member.

The present disclosure provides a bipolar electrosurgical instrument foruse in open surgery. The bipolar electrosurgical instrument includesfirst and second shafts each having a jaw member extending from a distalend thereof. A handle is disposed at proximal ends of the shafts foreffecting movement of the jaw members relative to one another about apivot member from a first position wherein the jaw members are disposedin spaced relation relative to one another to a second position whereinthe jaw members cooperate to grasp tissue therebetween. A firstconductive lead is adapted to connect to a first electrical potentialand a second conductive lead is adapted to connect to a secondelectrical potential. One of the first and second conductive leadsextends through the pivot to connect to a respective jaw member.

The present disclosure also provides a method for routing electricalleads through a bipolar electrosurgical instrument. The method includesforming first and second shafts with respective handles at proximal endsthereof and an end effector having two pivotably coupled jaw members atdistal ends thereof. One of the jaw members includes a pivot memberintegrally formed thereon. The pivot member is configured to receive oneof a first conductive lead and a second conductive lead therethrough. Astep of the method includes coupling the first and second leads to oneof the first and second shafts and routing each of the first and secondconductive leads therethrough. One of the first and second conductiveleads is coupled directly to one of the jaw members and one of the firstand second conductive leads is routed through the pivot member and tothe other jaw member.

BRIEF DESCRIPTION OF THE DRAWING

Various embodiments of the present disclosure are described hereinbelowwith references to the drawings, wherein:

FIG. 1 is a side, perspective view of an open forceps according to anembodiment of the present disclosure;

FIG. 2 is a enlarged view of the indicated area of detail in FIG. 1showing an end effector assembly of the open forceps depicted in FIG. 1;

FIG. 3 is an internal, side view of a jaw member associated with the endeffector assembly depicted in FIG. 2 showing the inner-workingcomponents thereof;

FIG. 4 is a enlarged view of the indicated area of detail in FIG. 3showing a pivot member associated with the open forceps depicted in FIG.1;

FIG. 5 is a side view of the jaw members with one of the jaw membersshown in phantom illustrating a wire routed through the pivot member ofFIG. 4; and

FIGS. 6A-6C are perspective views illustrating the jaw members invarious positions.

DETAILED DESCRIPTION

Detailed embodiments of the present disclosure are disclosed herein;however, the disclosed embodiments are merely examples of thedisclosure, which may be embodied in various forms. Therefore, specificstructural and functional details disclosed herein are not to beinterpreted as limiting, but merely as a basis for the claims and as arepresentative basis for teaching one skilled in the art to variouslyemploy the present disclosure in virtually any appropriately detailedstructure.

Referring now to FIGS. 1-6C, and initially with reference to FIG. 1, aforceps 10 for use with open surgical procedures is illustrated. Forceps10 includes elongated shaft portions 12 a and 12 b each having aproximal end 16 a and 16 b, respectively, and a distal end 14 a and 14b, respectively. The forceps 10 includes an end effector assembly 100that attaches to distal ends 14 a and 14 b of shafts 12 a and 12 b,respectively. The end effector assembly 100 includes a pair of opposingjaw members 110 and 120 that are pivotably connected about a pivotmember 150 (pivot 150).

In the drawings and in the descriptions which follow, the term“proximal”, as is traditional, will refer to the end of the forceps 10which is closer to the user, while the term “distal” will refer to theend which is further from the user.

Shaft 12 a includes a handle 17 a and shaft 12 b includes handle 17 b.Finger holes 18 a and 18 b are respectively disposed at the proximalends 16 a and 16 b for receiving a finger of the user. As can beappreciated, finger holes 18 a and 18 b facilitate movement of theshafts 12 a and 12 b relative to one another which, in turn, pivot thejaw members 110 and 120 from an open position (FIGS. 6A and 6B) whereinthe jaw members 110 and 120 are disposed in spaced relation relative toone another to a clamping or closed position (FIGS. 1, 2, 5 and 6C)wherein the jaw members 110 and 120 cooperate to grasp tissuetherebetween.

One of the shafts, e.g., 12 b, includes a proximal shaft connector 19that is designed to connect the forceps 10 to a source ofelectrosurgical energy such as an electrosurgical generator (not shown).More particularly, proximal shaft connector 19 mechanically cooperatesto secure an electrosurgical cable 210 to the forceps 10 such that theuser may selectively apply electrosurgical energy as needed. Theproximal end of the cable 210 includes a plug (not shown) having a pairof prongs which are configured to electrically and mechanically engagethe electrosurgical energy generator. The interior of cable 210 houses apair of leads 210 a and 210 b (FIG. 1) which conduct the differentelectrical potentials from the electrosurgical generator to the jawmembers 110 and 120, as explained in greater detail below.

In certain embodiments, a ratchet (not shown) may be operably coupled tothe forceps 10 for selectively locking the jaw members 110 and 120relative to one another at various positions during pivoting.

For a more detailed description of the forceps 10 including the ratchet,end effector 100 including jaw members 110 and 120 (and operativecomponents associated therewith), and electrosurgical cable 210(including line-feed configurations and/or connections), reference ismade to commonly owned U.S. Pat. No. 7,329,256 to Johnson et al., filedon Dec. 23, 2005.

Referring now to FIG. 2, an enlarged view of the end effector 100 isshown. End effector 100 includes opposing jaw members 110 and 120 thatare pivotably coupled to each other via the pivot 150 that is integrallyformed with one of the jaw members, e.g., jaw member 110. Jaw members110 and 120 including pivot 150 are configured such that the leads 210 aand 210 b connect to the respective jaw members 110 and 120 without theneed to “loop” one or both of the leads 210 a and 210 b around the pivot150 such that exposure of the leads 210 a and 210 b to the surgicalenvironment is minimized, if not completely eliminated. In theillustrated embodiment, jaw member 110 is supported on shaft 12 a atdistal end 14 a thereof and jaw member 120 is supported on shaft 12 b ata distal end 14 b thereof (FIG. 1).

Referring to FIG. 3, jaw member 110 is shown in unassembled and detachedfrom jaw member 120. Jaw member 110 includes a jaw housing 117 havingproximal and distal ends 117 a and 117 b. Distal end 117 b is configuredto support a seal plate 118 that is isolated from the rest of the jawhousing 117. Proximal end 117 a is configured to support the pivot 150.In the illustrated embodiment, the proximal end 117 a is elongated witha generally rectangular configuration that may include an arcuate orcurved proximal portion (not shown).

In the embodiment illustrated in the representative figures a generallylongitudinal channel 130 of suitable dimensions extends substantiallyalong a length of the proximal end 117 a (as best seen in FIG. 3). Thechannel 130 is configured to receive a cutting element or the like,e.g., a knife blade (not shown). More particularly, the channel 130 isconfigured such that the cutting element may be translated therethroughfor cutting or severing tissue that has been electrosurgically orotherwise treated. The channel 130 is also configured to align thecutting element with a longitudinal knife channel that is operablydisposed on one or both of the jaw members 110 and 120. For purposesherein, it may be assumed that the longitudinal knife channel isoperably disposed on both the jaw members 110 and 120. The depth of thechannel 130 is of such dimensions that the lead 210 a does not impedeand/or contact the knife blade when the knife blade is translatedthrough the channel 130 and the longitudinal knife channel on the jawmembers 110 and 120. To this end, an area “A” (FIG. 4) is definedbetween a pair of sidewalls 130 a and 130 b that defines the channel130.

As can be appreciated, in the instance where the forceps 10 is notconfigured to cut or sever tissue, the jaw member 110 may be configuredwithout the slot 130; this of course will depend on the contemplateduses of a manufacturer, a specific surgical procedure, etc.

Referring now to FIG. 4, a wire or lead guide slot 152 is suitablyproportioned and operably disposed on the proximal end 117 a of the jawhousing 110. The lead guide slot 152 includes a generally elongatedconfiguration and is configured to house the lead 210 a and provide amechanical interface or “pathway” between the lead 210 a and seal plate118. Lead 210 a may be secured within the lead guide slot 152 via one ormore suitable securement methods, e.g., press-fit, adhesive, etc. In theillustrated embodiment, the lead 210 a is press-fit in the lead guideslot 152 and, subsequently, overmolded thereto such that the distal endof lead 210 a is in electrical communication with the seal plate 118, asbest seen in FIGS. 3 and 5. The distal end of the lead 210 a may besecured to seal plate 118 via any suitable method, such as crimping,soldering, etc. Securing lead 210 a in this manner facilitatesmaintaining the lead 210 a in a relatively fixed position while alsoallowing the lead 210 a to “flex” or “bend” when the jaw members 110 and120 are moved from the open to the clamped position, and vice versa (seeFIGS. 6A-6C). In the illustrated embodiment, the lead guide slot 152 isoriented at an angle with respect to the longitudinal channel 130, seeFIGS. 3 and 4. Disposing the lead guide slot 152 at an angle withrespect to the longitudinal channel 130 relieves the stress on the lead210 a when the jaw members 110 and 120 are moved from the open to theclamped position, and vice versa.

To facilitate placement and/or securement of the lead 210 a within thelead guide slot 152, a proximal end 153 of the lead guide slot 152 isoperably disposed in close proximity to the pivot 150 and adjacent thechannel 130, as best seen in FIG. 4. The proximal end 153 of the leadguide slot 152 does not breach the area “A” defined by the pair ofsidewalls 130 a and 130 b of the channel 130; this facilitates keepingthe knife blade and the lead 210 a from contacting each other duringtranslation of knife blade through the channel 130.

With reference again to FIGS. 3 and 4, pivot 150 is bifurcated includinga pair of spaced-apart members 150 a and 150 b. Members 150 a and 150 bare operably disposed on each side of the longitudinal channel 130, seeFIG. 3. In the illustrated embodiment, the members 150 a and 150 b arespaced-apart from each other at a distance that is at least as equal toa width of the longitudinal channel 130; this facilitates translation ofthe knife blade therethrough.

Each of members 150 a and 150 b includes a generally half-cylindrical orsemi-cylindrical configuration that together form a split cylindricalconfiguration configured for engagement with a corresponding aperture176 on the jaw member 120, to be described in greater detail below. Moreparticularly, member 150 a includes a stepped configuration having abase portion 154 a for supporting an extension 154 b thereon (FIGS. 3and 4) that is configured to engage a pivot plate 160 operably disposedon the jaw member 120. Likewise, member 150 b includes a steppedconfiguration having a base portion 156 a for supporting an extension156 b thereon (FIGS. 3 and 4) that is configured to engage pivot plate160 operably disposed on the jaw member 120.

One or more jaw aperture stops 162 (one jaw aperture stop 162 (“stop162”) is illustrated in the representative drawings) of suitableproportion are associated with the pivot 150 (FIGS. 3, 4, 6B and 6C).The stop 162 is configured to limit movement of the jaw members 110 and120 to a predetermined point when the jaw members 110 and 120 are movedto the open position. With this purpose in mind, stop 162 is operablydisposed adjacent one of the two spaced-apart members 150 a and 150 b.For illustrative purposes, the stop 162 is shown disposed adjacentspaced-apart member 150 b. Stop 162 may include any suitable shape andis configured to slidably reside within a corresponding groove 164disposed on the jaw member 120 (FIGS. 5 and 6C). Stop 162 includes agenerally arcuate or curved proximal end, edge or sidewall 166 (FIGS. 4and 6B) that is contoured to match a corresponding arcuate or curvedend, edge or sidewall 168 that partially defines the groove 164 (as bestseen in FIG. 6C). Matching the contours of the sidewalls 166 and 168facilitates rotating the jaw members 110 and 120 from the open to closedpositions. When the jaw members 110 and 120 have moved a predetermineddistance, the sidewall 166 of the stop 162 contacts the sidewall 168 ofthe groove 164 and prevents further movement of the jaw members 110 and120 away from each other (see FIG. 6B in combination with FIG. 6C); thisincreases the operational life expectancy of the lead 210 a and, thus,the operational life expectancy of the forceps 10.

Referring to FIGS. 5 and 6A-6C, jaw member 120 is illustrated inphantom. Jaw member 120 and jaw member 110 are substantially identicalto one another. In view thereof, only those features unique to jawmember 120 are described herein.

A wire or lead guide slot 155 is suitably proportioned and operablydisposed on the proximal end 127 a of the jaw housing 120 (shown inphantom in FIG. 6A). The lead guide slot 155 provides a mechanicalinterface or “pathway” between the lead 210 b and the seal plate 128.Lead 210 b may be secured within the lead guide slot 155 and to the jawhousing 127 via one or more of the aforementioned securement methods,e.g., press-fit, adhesive, etc. In the illustrated embodiment, the lead210 b is press-fit in the lead guide slot 155, the distal end crimped orsoldered to the jaw housing 127 adjacent the seal plate 128 and,subsequently, overmolded thereto such that the lead 210 b is inelectrical communication with the seal plate 128. A proximal end of thelead guide slot 155 opens into a raceway 170 (FIGS. 6A-6C).

Raceway 170 is operably disposed at the proximal end 127 a of the jawhousing 127 and includes a generally elongated configuration with anarrowed proximal end 172 and broadened distal end 174. The raceway 170provides a path or a point of egress for the leads 210 a and 210 b fromthe shaft 12 b into the jaw housings 117 and 127.

Proximal end 172 of the raceway is configured such that when the leads210 a and 210 b are positioned therein, the leads 210 a and 210 b remainin a substantially fixed orientation, i.e., the leads 210 a and 210 bare “press fit” into the proximal end 172 of the raceway.

In certain embodiments, it may prove useful to fixedly secure the leads210 a and 210 b within the proximal end 172 of the raceway 170.

Distal end 174 of the raceway 170 opens into the groove 164 defined bythe arcuate or curved sidewall 168 (FIGS. 6B and 6C). Moreover, thedistal end 174 of the raceway 170 opens into the area “A” definedbetween the two spaced-apart members 150 a and 150 b, see FIGS. 4 and6A-6C, for example. This facilitates routing the lead 210 a through theraceway 170 and between the two spaced-apart members 150 a and 150 b,such that the lead 210 a may be ultimately secured within the lead guideslot 152, see FIG. 3.

A generally circumferential opening 176 of suitable proportion isoperably disposed on the jaw member 120 (FIGS. 2 and 6A-6C). The opening176 is configured to receive the pivot 150 including the twospaced-apart members 150 a and 150 b such that the pivot 150 includingthe two spaced-apart members 150 a and 150 b are rotatably movablethereabout.

A circumferential groove 178 of suitable proportion is operably disposedwithin the opening 176 and is configured to accommodate rotatablemovement of the pivot plate 160 (FIG. 2). To this end, the groove 178includes a circumferential lip or flange (not explicitly shown) that isconfigured to provide a seat for the pivot plate 160.

Pivot plate 160 is seated on the circumferential flange of the groove178 and within the opening 176. Pivot plate 160 includes two halfcylindrical openings 161 and 163. Openings 161 and 163 are configured tocouple to respective spaced-apart members 150 a and 150 b, as best seenin FIG. 2. Openings 161 and 163 may couple to the respectivespaced-apart members 150 a and 150 b via one or more suitable couplingmethods, e.g., solder joint, braze joint, weld joint, adhesive,press-fit, friction-fit, etc. In the illustrated embodiment, theopenings 161 and 163 are coupled to the respective spaced-apart members150 a and 150 b via a spot weld.

In an assembled configuration, the forceps 10 is utilized in a mannerthat is conventional in the relevant arts. More particularly, anoperator grasps the forceps 10, moves the jaw members 110 and 120 to theopen position, positions tissue between the jaw members 110 and 120,clamps down on the tissue therebetween and treats the tissue, e.g.,seals the tissue. In certain instances, a knife blade is, subsequently,translated through the jaw members 110 and 120. However, unlikeconventional forceps, where one or more of the leads 210 a and 210 b areexposed to the surgical environment when the jaw members 110 and 120 aremoved to the open position, use of the forceps 10 with one of the leads,e.g., lead 210 a, routed through the pivot 150 does not expose the lead210 a to the surgical environment, see FIGS. 6A-6C, for example.Accordingly, the risk of compromising the integrity of the lead 210 a isdiminished, if not eliminated.

From the foregoing and with reference to the various figure drawings,those skilled in the art will appreciate that certain modifications canalso be made to the present disclosure without departing from the scopeof the same. For example, in embodiments, it may prove useful to disposethe stop 162 on the jaw member without the pivot 150 and dispose thecorresponding sidewall 168 on the jaw member with the pivot 150.

A method for routing electrical leads 210 a and 210 b through a bipolarelectrosurgical instrument, e.g., forceps 10, is also disclosed. A stepof the method includes forming first and second shafts 12 a and 12 bwith respective handles 17 a and 17 b at proximal ends thereof and anend effector 100 having two pivotably coupled jaw members 110 and 120 atdistal ends thereof. One of the jaw members, e.g., jaw member 110,includes a pivot 150 formed integrally thereon. The pivot 150 isconfigured to receive one of the electrical leads, e.g., electrical lead210 a, therethrough. The method includes coupling the electrical leads210 a and 210 b to one of the first and second shafts, e.g., shaft 12 b,and routing each of the electrical leads 210 a and 210 b therethrough.Electrical lead 210 b is coupled directly to the jaw member 120 andelectrical lead 210 a is routed through the pivot 150 and to the jawmember 110.

While several embodiments of the disclosure have been shown in thedrawings, it is not intended that the disclosure be limited thereto, asit is intended that the disclosure be as broad in scope as the art willallow and that the specification be read likewise. Therefore, the abovedescription should not be construed as limiting, but merely asexemplifications of particular embodiments. Those skilled in the artwill envision other modifications within the scope and spirit of theclaims appended hereto.

What is claimed is:
 1. A bipolar electrosurgical instrument, comprising:first and second shafts each having a jaw member extending from a distalend thereof and movable relative to one another about a pivot between afirst position wherein the jaw members are disposed in spaced relationrelative to one another and a second position wherein the jaw memberscooperate for grasping tissue therebetween; a knife channel extending atleast partially through each of the jaw members; a pair of conductiveleads adapted to provide a first electrical potential to the jaw memberof the first shaft and a second electrical potential to the jaw memberof the second shaft; and a wire guide slot disposed on at least one ofthe first or second jaw members, the wire guide slot configured toreceive at least one of the pair of conductive leads therethrough suchthat the pair of conductive leads are maintained in a relatively fixedposition during movement of the first and second jaw members between thefirst and second positions.
 2. The bipolar electrosurgical instrumentaccording to claim 1, wherein the pivot includes a pair of spaced-apartmembers disposed in opposing relation about a longitudinal channelextending therebetween, the longitudinal channel configured to receiveat least one of the pair of conductive leads therethrough.
 3. Thebipolar electrosurgical instrument according to claim 2, wherein each ofthe pair of spaced-apart members includes a generally semi-cylindricalshape.
 4. The bipolar electrosurgical instrument according to claim 2,wherein the pair of spaced-apart members are configured to engage anopening defined in at least one of the first or second jaw members. 5.The bipolar electrosurgical instrument according to claim 4, whereineach of the pair of spaced-apart members comprises a base portion and anextension portion.
 6. The bipolar electrosurgical instrument accordingto claim 5, wherein each extension portion is configured to engage acorresponding opening defined in a pivot plate to operably couple thejaw members together.
 7. The bipolar electrosurgical instrumentaccording to claim 6, wherein the pivot plate is rotatable within acircumferential groove defined in at least one of the jaw members and isconfigured to facilitate rotation of the jaw members about the pivot. 8.The bipolar electrosurgical instrument according to claim 1, wherein alongitudinal groove is defined along a proximal end of at least one ofthe jaw members and in alignment with the knife channel.
 9. The bipolarelectrosurgical instrument according to claim 8, further comprising aknife configured to reciprocate through the longitudinal groove and theknife channel to cut tissue grasped between the jaw members.
 10. Thebipolar electrosurgical instrument according to claim 1, furthercomprising a shaft connector coupled to at least one of the first andsecond shafts, the shaft connector configured to connect the bipolarelectrosurgical instrument to a source of electrosurgical energy. 11.The bipolar electrosurgical instrument according to claim 1, wherein atleast one of the pair of conductive leads extends through the pivot. 12.An end effector for an electrosurgical instrument, comprising: first andsecond jaw members movable relative to one another about a pivot betweena first position wherein the jaw members are disposed in spaced relationrelative to one another and a second position wherein the jaw memberscooperate for grasping tissue therebetween; a longitudinal groovedefined along a proximal end of at least one of the jaw members and inalignment with a knife channel extending at least partially through eachof the first and second jaw members; a pair of conductive leads adaptedto provide a first electrical potential to the first jaw member and asecond electrical potential to the second jaw member; and a wire guideslot disposed on at least one of the jaw members, the wire guide slotconfigured to receive at least one of the pair of conductive leadstherethrough such that the pair of conductive leads are maintained in arelatively fixed position during movement of the first and second jawmembers between the first and second positions.
 13. The end effector foran electrosurgical instrument according to claim 12, wherein the pivotincludes a pair of spaced-apart members disposed in opposing relationabout a longitudinal channel extending therebetween, the longitudinalchannel configured to receive at least one of the pair of conductiveleads therethrough.
 14. The end effector for an electrosurgicalinstrument according to claim 13, wherein each of the pair ofspaced-apart members includes a generally semi-cylindrical shape. 15.The end effector for an electrosurgical instrument according to claim13, wherein the pair of spaced-apart members are configured to engage anopening defined in at least one of the first or second jaw members. 16.The end effector for an electrosurgical instrument according to claim15, wherein each of the pair of spaced-apart members comprises a baseportion and an extension portion.
 17. The end effector for anelectrosurgical instrument according to claim 12, further comprising apivot plate configured to operably couple to the pivot and to rotatewithin a circumferential groove defined in at least one of the jawmembers during movement of the jaw members between the first and secondpositions.
 18. The end effector for an electrosurgical instrumentaccording to claim 12, further including a knife configured toreciprocate through the longitudinal groove and the knife channel to cuttissue grasped between the jaw members.